J/PAZh/38/95 Proper motions and photometry in NGC 2323 (Frolov+, 2012)
Investigation of the open star cluster NGC 2323 (M50).
Based on the proper motions and photometry of its constituent stars.
Frolov V.N., Ananjevskaja Yu.K., Polyakov E.V.
<Pis'ma Astron. Zh. 38, 95 (2012)>
=2012PAZh...38...95F 2012PAZh...38...95F
=2012AstL...38...74F 2012AstL...38...74F
ADC_Keywords: Clusters, open ; Photometry, UBV ; Photometry, infrared ;
Proper motions
Keywords: open star clusters: NGC 2323, photometry, proper motions
Abstract:
The results of a comprehensive study of the Galactic open cluster
NGC 2323 are presented. The positions of stars to a limiting magnitude
B≤16.7mag in a 42.5x42.5arcmin area centered on the cluster were
measured on six plates from the Pulkovo normal astrograph with a
maximum epoch difference of 60yr. The measurements were performed with
the Pulkovo "Fantasy" automated measuring system upgraded in 2010. The
corresponding areas from the USNO-A2.0, USNO-B1, and 2MASS catalogues
were used as additional plates. As a result, the relative proper
motions of stars were obtained with a root-mean-square error of
5.85mas/yr. A catalogue of UBV and JHK magnitudes for objects in the
investigated area was compiled from available published resources. The
astrometric selection of cluster members was made by the maximum
likelihood method. A high individual cluster membership probability of
a star (P≥80%) served as the first selection criterion. The position
of a star on the photometric color-magnitude (V-(B-V), J-(J-K))
diagrams of the cluster was considered as the second criterion. The
position of an object on the color- color ((U-B)-(B-V), (J-H)-(J-K))
diagrams served as the third criterion. On the basis of these
criteria, it was established that 508 stars are members of NGC 2323.
These data were used to refine the physical parameters of the cluster:
the mean reddening E(B-V)=0.25mag, the true distance modulus
(V-MV)=9.85mag, and the cluster age of about 140Myr from the grid of
isochrones computed by the Padova group for solar chemical
composition. Two tables contain the catalogues of proper motions and
photometry for stars in the area. The luminosity and mass functions
were constructed. The cluster membership of red and blue giants,
variable, double, and multiple stars was considered. The position of
the cluster center was improved: alpha=07:02:47.5, delta=-08:20:16
(2000.0).
Description:
The plates taken with the Pulkovo normal astrograph (the scale is
60arcsec/mm) from 1930 to 1990 constituted the main astrometric
material.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table3.dat 80 1103 Stars proper motions and estimations of their
belonging to the cluster
table5.dat 52 1034 Photometric data and cluster membership for
stars in the NGC 2323 area
--------------------------------------------------------------------------------
See also:
I/252 : The USNO-A2.0 Catalogue (Monet+ 1998)
J/A+AS/128/131 : UBV photometry of NGC 2323 (Claria+ 1998)
J/MNRAS/392/1456 : VIc photometry of NGC 2323 low-mass stars (Irwin+, 2009)
Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 I4 --- Seq Star number according to our study
6- 18 A13 --- USNO-A2.0 ? Star designation in USNO-A 2.0
20- 25 F6.2 arcmin Xpos Rectangular coordinate X of star relative to
the star N 680 (at epoch 1930.1)
27- 32 F6.2 arcmin Ypos Rectangular coordinate Y of star relative to
the star N 680 (at epoch 1930.1)
34- 39 F6.1 mas/yr pmX Proper motion of the star along X
41- 44 F4.1 mas/yr e_pmX rms uncertainty on pmX
46- 51 F6.1 mas/yr pmY Proper motion along Y
53- 56 F4.1 mas/yr e_pmY rms uncertainty on pmY
58 I1 --- Pl Number of plates
60- 61 I2 % Mm Membership probability
63- 64 A2 --- bl [bl] "bl" marks blends.
66- 80 A15 --- Notes ? Other identifications (1)
--------------------------------------------------------------------------------
Note (1): Notes contains the numbers of the star in the
BD, HD, IRAS, Tycho, ROSAT, IRAS and Tycho catalogues.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table5.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 I4 --- Seq Star number according to our study
6- 10 F5.2 mag Vmag V magnitude
12- 16 F5.2 mag B-V B-V color index
18- 22 F5.2 mag U-B ? U-B color index
24- 25 A2 --- Ref Source of photometry (1)
27- 32 F6.3 mag Jmag ? 2MASS J magnitude
34- 39 F6.3 mag Hmag ? 2MASS H magnitude
41- 47 F7.4 mag Kmag ? 2MASS Ks magnitude
48- 50 A3 --- CM [II III] Cluster membership (2 or 3 criteria)
52 A1 --- uph [:] : marks raising doubts photometry
--------------------------------------------------------------------------------
Note (1): Source of photometry as follows:
Cl = Claria et al., 1998, Cat. J/A+AS/128/131
SH = Sharma et al., 2006, Cat. J/AJ/132/1669
K = Kalirai et al., 2003AJ....126.1402K 2003AJ....126.1402K
H = Hoag et al., 1961PUSNO..17..343H 1961PUSNO..17..343H
Mo = Mostafa et al., 1983JASEg...5...23M 1983JASEg...5...23M
2M = 2MASS, Cat. II/246
--------------------------------------------------------------------------------
Acknowledgements:
Vladimir Frolov, Vfrol(at)gao.spb.ru
(End) Vladimir Frolov [GAO, Russia], Patricia Vannier [CDS] 20-Feb-2012